1. Field of the Invention
This invention relates to an image reading apparatus provided with a reading member such as a CCD and for reading the image of an original.
2. Related Background Art
FIGS. 5 and 6 of the accompanying drawings show an image reading apparatus which is the background art of the present invention. This apparatus is an apparatus in which an original is moved and the image of the both sides of the original are read, and has first image reading means for reading the lower surface of the original, and second image reading means for reading the upper surface of the original, and can read the images of the both sides of the original at a time. When sides is to be effected, the original is automatically fed with the first image reading means fixed, and lights are applied from discrete light sources to the both sides of the original being conveyed, and the reflected lights are received and the images are read.
As shown in FIG. 5, the original placed on an original stacking plate 100 is pulled into the apparatus by a pulling-in portion. The pulled-in original is moved by a separating roller 101, a discharge roller 102 and a driven roller 103. In the meantime, the front surface of the original is illuminated by a lamp 104, and the optical information of the original is directed to a lens 106 by a mirror 105. The lens 106 converges the optical information of the original and applies it to a CCD 107. The optical information which has entered the CCD 107 is converted into an electrical signal and as the result, the information of the front surface of the original is read by the CCD.
Further, design is made such that when jam occurs during the conveyance of the original, a reading unit can be pivotally moved about a hinge 108 to open a portion of a conveying path so that a user can smoothly carry out jam treatment (see FIG. 6).
Now, when the light is applied from the light source, heat is generated from the light source and the temperature in the apparatus rises. Particularly when the upper surface of the original is to be read, the upper portion of the apparatus in which the temperature is liable to rise is liable to be affected by the heat thereof because as a matter of course, the reading means is disposed above the original.
Also, in the trend to a higher speed and a higher quality of image, the temperature rise of the light source lamp has become great. As indicated by arrows A in FIG. 5, heated air moves upward and therefore, the temperature of the CCD which is an image reading member disposed above the light source rises and thus, there has been the possibility that the image cannot be read with good accuracy or in the case of a CCD capable of reading a color image, the gelatin matter of a color filter melts out and an inconvenience may occur to the CCD.
Also, while as shown in FIG. 6, a reading unit for reading the upper side of the original including an original upper side conveying path is pivotally moved to thereby open the conveying path and carry out jam treatment and maintenance, there is a case where paper powder and toner adhering to the conveying path or stripped-off toner and dust fall off the conveying path with the pivotally moving operation and fall downward as indicated by arrow B in FIG. 6. If at this time, the CCD is at a short distance from the center of pivotal movement, the CCD may be located below the locus of the pivotal movement of the conveying path and therefore, it has sometimes happened that the CCD is stained by the falling paper powder, toner and dust and the image of the original cannot be read accurately.